Half home movie, half family saga, Kimberly Reed's documentary, Prodigal Sons, is painful to watch but also honest and original. The "prodigal sons" aren't prodigal in the biblical sense of the word, nor are they the stuff of the all-American mom-and-apple-pie family.

Kimberly Reed is a transgender lesbian formerly known as Paul McKerrow, who was co-captain of his high school football team, valedictorian and voted most likely to succeed. Kim's older brother, Marc, an adopted child, suffers from seizures and mood disorders as a result of a brain injury many years earlier. Held back in preschool, Marc ended up in the same class with little brother Paul, with whom there was always a high degree of sibling rivalry.

When Kimberly returns from New York to her hometown of Helena, Montana, for a high school class reunion, she hopes to reconcile with her brother, whom she hasn't seen in years. And, at first, things appear to be going well. Kim is accepted by her former classmates ("All of us have changed. All of us are different," says one) and her mother, Carol. And Marc seems jovial enough.

For a while. Intent on maintaining the relationship, Kim later visits Marc and his family at their home in Oregon, and Marc goes out of control. Matters are patched up again when Marc discovers his biological mother (who has just died), and Marc's family together with Kim are invited to visit family connections abroad. And then things go out of control again.

Prodigal Sons is not like watching a train wreck: It's like watching a series of train wrecks. Marc's discovery of a surprising connection with Orson Welles provides a high; his violent outbursts bring everything crashing down. While Kim works through issues of her own identity and painful memories of adolescent anxieties and the stresses of her "transformation" while she was living and working in San Francisco, Marc tries, less successfully, to come to terms with his own genes and the storms inside his damaged brain.

The film's hand-held camera work is annoying but, given the subject matter and the on-the-spot filmmaking, probably unavoidable. Kim Reed narrates.

Review our reviews at letters@pacificsun.com.

Are you receiving Express, our free daily e-mail edition? See a sample and sign-up for Express.